Meconium plug syndrome is colonic obstruction caused by thick meconium. Diagnosis is based on radiographic contrast enema and sometimes testing for Hirschsprung disease (because failure to pass meconium in the first 24 hours occurs in Hirschsprung disease as well). Treatment is radiographic contrast enema; surgical decompression is rarely required.
Meconium plug syndrome usually occurs in infants who are otherwise healthy and has an incidence of 1 in 500 live births.
Meconium plug syndrome is generally regarded as a functional immaturity of the colon, resulting in failure to pass the first stool.
Etiology of Meconium Plug Syndrome
Meconium plug syndrome is more common among
Infants of mothers with diabetes
Infants of mothers treated with magnesium sulfate for eclampsia, preeclampsia, or preterm labor
One study noted that 16% of cases of meconium plug syndrome were associated with magnesium tocolysis (1). Hirschsprung disease is present in about 10 to 40% of infants with meconium plug syndrome (2). Meconium plug syndrome is also associated with cystic fibrosis.
Etiology references
1. Cuenca AG, Ali AS, Kays DW, Islam S: "Pulling the plug"--management of meconium plug syndrome in neonates. J Surg Res 175(2):e43-e46, 2012. doi: 10.1016/j.jss.2012.01.029
2. Buonpane C, Lautz TB, Hu YY: Should we look for Hirschsprung disease in all children with meconium plug syndrome? J Pediatr Surg 54(6):1164, 2019. doi: 10.1016/j.jpedsurg.2019.02.036
Symptoms and Signs of Meconium Plug Syndrome
Infants present in the first few days of life with failure to pass stools, abdominal distention, and vomiting. Thick, inspissated, rubbery meconium forms a cast of the colon, resulting in complete obstruction.
Diagnosis of Meconium Plug Syndrome
Radiographic contrast enema
Sometimes testing for Hirschsprung disease
Diagnosis of meconium plug syndrome is of exclusion and should be differentiated primarily from Hirschsprung disease, especially if symptoms of distal obstruction persist despite passing the meconium plug.
Plain abdominal x-rays are nonspecific and can show signs of low intestinal obstruction. Conversely, contrast enema shows the characteristic appearance of the outline of the inspissated meconium against the wall of the colon, providing a double-contrast impression (1). Unlike meconium ileus, microcolon is not typically seen on x-ray with meconium plug syndrome because meconium plug syndrome is a distal process.
Patients with meconium plug syndrome should be tested for cystic fibrosis.
Diagnosis reference
1. Manzoor A, Talat N, Adnan HM, et al: Contrast Enema: Solving Diagnostic Dilemmas in Neonates With Lower Intestinal Obstruction. Cureus 14(3):e23458, 2022. doi: 10.7759/cureus.23458
Treatment of Meconium Plug Syndrome
Radiographic contrast enema
The water-soluble contrast enema can be therapeutic by separating the plug from the intestinal wall and expelling it. Occasionally, repeated enemas are required.
Rarely, surgical decompression is required. Although most infants are healthy thereafter, diagnostic studies may be needed to rule out Hirschsprung disease or cystic fibrosis.
